Furnace.



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By jails/4i inrneys:

G. PRESQOTT. PURNAGE.

APPLICATION FILED DEQ. 23i 1907.

Patented Jan.12,1909. v

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FURNAGB.

A APPLIOATIONI'ILED DEG. 23, 1.907. 909,21 8a v A Patented Jan. 12, 1909. ZBEEETS-BHEBT 2.

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1r: Nonms Perses co., v AsmNamN. g 4 c UNITED STATES PATENT OFFICE.

GEORGE PRESCOTT, OF MINNEAPOLIS, MINNESOTA.

FURNACE Application filed December 23, 1907.

T o all whom it may concern:

Be it known that I, GEORGE PREsooTT, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Furnaces; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art 'to which it appertains to make and use the same.

My invention relates to furnaces and especially those that are used in connection with boilers for Generating steam, and has for its object to provide certain improvements whereby the combustion of the furnace is rendered more complete, thereby accomplishing two important results, to-wit, economy in the use of fuel and the burning of the smoke.

To the above ends the invention consists of the novel devices and combinations of devices hereinafter described and defined in the claims.

In the accompanying drawings which illustrate the invention, like characters indicate like parts throughout the several views.

Referring to the drawings, Figure 1 is a view showing, in vertical longitudinal section, a furnace with my invention applied thereto and showing in full side elevation a horizontal boiler located in the furnace; and Fig. 2 is a transverse vertical section taken on the line :v2 m2 of Fig. 1, but with some parts broken away.

The numeral 1 indicates the exterior brick-work or masonry of the furnace, within which is placed a horizontal boiler 2, shown as of standard construction. Instead of the boiler shown a water tube boiler of any suitable or approved construction may be employed.

The intermediate portion of the boiler 2 overlies a vertical transversely extended fire wall 3, from which a re arch 4 projects forward and assists in forming a primary combustion chamber. The lire arch 4 terminates considerably short of the front wall of the main brick-work 1, so as to leave a large draft passage 5 at the front of the furnace; and just above this passage 5 is an upper or secondary tire arch 6 that protects Specification of Letters Patent.

Patented Jan. 12, 1909.

Serial No. 407,817.

of combustion, as indicated by arrows marked on Fig. 1. The grates 7 are secured in the usual way below the arch 4. The products of combustion or flames pass rearward from the ame passage 5 to the rear end of the boiler to-wit: into the secondary combustion chamber, thence through the usual lines thereof (not shown) into the smoke box S, and thence out through the stack 9. The fire wall 3 is formed with a vertical transversely extended air chamber 10 which has an air induction port 11, which, as shown, opens through one of the side walls of the brick-work 1. At its upper portion the air chamber 10 opens into the primary combustion chamber of the furnace below the arch 4 through a multiplicity of air passages 12, preferably formed in the brick-work of the side wall.

Located within the air chamber 10 is a radiator, preferably formed by a pipe coil or alternated loop 13, one end of which is connected, by a steam supply pipe 14, to the dome of the boiler 2. In the steam supply pipe 14 is a valve 15. The other extremity of the pipe coil 13 extends outward through the air induction port 11 and is connected, by a pipe 16, to a perforated nozzle pipe 17, which latter, as shown, is passed through the rear wall of the brick-work l and extends transversely of the secondary chamber 1a just below and at the rear of the rear end of the boiler `2. The pipe 16 is provided with a valve 18, and the lower extremity of the coil 11 is provided with a valve 19. The

valve 19 should be normally closed as it serves only as a drain cock to draw o condensed water from the coil 13 and pipes connected thereto. The valve 18 should be opened or closed according to whether or not it is desired to use the nozzle pipe 17 to precipitate the soot. The valve 15 should be normally opened so that steam will be kept within the coil 13.

When the parts are thus adjusted and the furnace is in action, the heat radiated from the coil 13 superheats the air in the air chamber 10, and the said air, of course, is also heated to a certain extent by the direct radiation of heat through the tire wall 3. The air thus drawn into the chamber 10 through the air induction port 11 will be trst superheated by the means just noted and will be drawn into the primary combustion chamber of the furnace through the ports or passages 12 at the rear of said combustion chamber, and will be drawn along directly under the arch 4, where it will greatly intensify the draft and very greatly increase the intensity of the combustion by the supply of oxygen which it afl'ords. It is, of course,nevident that fresh hot air which effect in producing complete combustion. chamber will increase the combustion 4to a very much greater extent than cold air. It is also evident that the air is introduced where yit will have the most advantageous effect in producing complete combustion. In starting the furnace the greatest diiiiculty is experienced in electing such complete combustion that no smoke will escape from the furnace. To prevent the escape of smoke at such times thevalve 18 isopened so as to cause escape of a spray of steam through the products of combustion just before they enter the flues of the boiler. This spray of steam will precipitate all soot or incompletely burned particles and thus abate the smoke nuisance. Except when starting the furnace, however, this steam spraying device is vnot necessarily used.

vIt is further important to note that the steam delivered to the nozzle pipe 17 passes first through the coil 13 where the steam will be superheated by the heat radiated from thepfurnace into the air chamber 10. This superheated steam will not check, to any perceptible extent, the intensity of the combustion at the point where it is applied.

A furnace may be constructed as above described at small cost and will accomplish the primary object of this invention above set forth.

What I claim is:

'1. In a furnace, the combination of a `furnace chamber, and a boiler located therein, a fire wall dividing said chamber into a primary and secondary combustion chamber; a lire arch extending forwardly and into the primary combustion chamber from the top of said lire wall but terminating lshort of the front wall of the furnace chamber, a second lire arch extending rearwardly from the front wall of the furnace chamber, `and adaptedto overlap the front portion of the chamber below the first mentioned fire-arch and a steam pipe coil located in said air chamber for super-heating lthe air passing into the primary combustion chamber, substantially as described. Y v

- 2. In a furnace, the combination of a furnace chamber, and a boiler located therein,

a fire wall dividing said chamber `into a priy mary and secondary combustion chamber.; a

fire arch extending forwardly and into the primary combustion chamber from the top of said fire wall but terminating short of the front wall ofthe furnace chamber, a second fire arch extending rearwardly from the front wall of the furnace chamber, and

adapted to overlap the front portion of the first mentioned iirearch,` said second arch being located above the plane of and at a distance from said first mentioned arch, and also underlying and closely engaging the forward lowermost lportion of the boiler, said fire-wall 'having an air chamber therein, an induction port and a multiplicity of air escape ports in said air chamber, the lat-- ter opening into the primary combustion chamber below the iirst mentioned fire-arch, a steam pipe coil located in said air vchamber and connected to said boiler, and a steam pipe extending fr om said steam pipe coil and terminating in 'a nozzle pipe, located in position to discharge into the rear portion vof .said Vsecondary combustion chamber `on a line between the two lire arches, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses. v

GEORGE PaEsooT-T. Witnesses :v

KILGORE, F. D. MERCHANT. 

